fix booting of a Linux distro by forcing qcow format.
fix booting of a Linux distro by forcing qcow format.

For some reason, even if the volume has format qcow2, libvirt sets the disk
driver to "raw".

inercia/terraform-provider-libvirt,dmacvicar/terraform-provider-libvirt,flavio/terraform-provider-libvirt,deasmi/terraform-provider-libvirt,deasmi/terraform-provider-libvirt,deasmi/terraform-provider-libvirt,dmacvicar/terraform-provider-libvirt,dmacvicar/terraform-provider-libvirt